This invention relates to a clutch disc of an automotive friction clutch.
Generally, in a power transmitting system of an automobile, various vibration and noise are generated by synchronized torsional vibration of the system or backlash of gears in a transmission or a differential gear. In order to eliminate such a disadvantage, it is well known that a hysteresis characteristic of the clutch disc is controlled and that there exists an optimal hysteresis characteristic to reduce such vibration and noise corresponding to the amount of the vibration and the nature of the noise.
The prior art has proposed the utilization of nonlinear characteristic obtained by the internal hysteresis by using rubber for a torsional damper of the clutch disc. The prior art has also proposed the variation of the hysteresis characteristic of the cluth disc in response to the variation of a torsional angle of the clutch disc, for example, as is disclosed in Japanese Laid-Open Patent Publication No. 48-69936. However, according to the former teaching, it may not be anticipated that the above mentioned vibration and noise are sufficiently reduced, while according to the latter teaching, the invention has not yet been put to practical use because of the complicated structure and unsatisfactory durability.